Heating, ventilating, and air-conditioning (HVAC) systems provide temperature and humidity controlled air to residential, commercial, and industrial buildings. Air provided by the HVAC system may need to be at a specified temperature or humidified or dehumidified to meet comfort levels for occupancy, or to be within a range for electronics, or the like. Typically outside air is dehumidified and cooled if using an air conditioning system, and it is humidified and heated if using a heating system. The temperature and humidity mechanisms may be integrated or separate.
For example, with some conventional air conditioning systems, air is cooled below its dew point by passing it over cooling coils such that water is condensed out of the air. This usually results in air at a temperature below a comfort zone temperature. The air is then heated to bring it to a desired comfort zone temperature by mixing it with warmer air already in the space being cooled or by passing it over a heating coil. The excess cooling used to dehumidify the air decreases efficiency.
If a desiccant type dehumidifier is used in an air conditioning system, the desiccant removes water to dehumidify air in the dehumidification section. The dried air can then be cooled using a cooling coil to a desired comfort zone temperature. The desiccant is regenerated in a regeneration section where water is removed from the desiccant. The desiccant can then be reused in the dehumidification section. Depending on the capacity and type of the dehumidification and regeneration sections, desiccant can be blown out of the sections at high air flow rates. A high flow rate of air flowing through the chamber containing the desiccant contacts the desiccant, entrains desiccant droplets or vapor, and causes desiccant to be lost from the HVAC system. The loss of desiccant through blow-out from the chamber during high air flow rate conditions can impair the function of the dehumidifier if insufficient desiccant is present, or can cause other problems.